1. Field of the Invention
This invention relates to a photographic camera system with an electronic flash sneak charge and, more particularly, to a photographic camera system with an electronic flash for which the apparent charging time subsequent to an exposure cycle is reduced by a sneak charge.
2. Description of the Prior Art
Fully automatic cameras most recently sold by Polaroid Corporation, of Cambridge, Mass., U.S.A., are intended to be used with well-known instant developing film cassettes which include an integral power supply. The power supply forming an integral part of the cassette is a battery which supplies electrical energy for the operation of components of the camera in which the film units are exposed and processed. The cameras include various subsystems which, for instance, may be an exposure control system, a film transport system, a dark slide removal system, a motor powered mechanism for transporting and processing an exposed film unit, and electronic logic circuits that provide a sequence control of functions. In addition, it is highly desirable that such cameras be adapted for use with an electronic flash and that the electronic flash be powered from the film cassette battery as is described in U.S. Pat. No. 4,074,295, entitled "Compact Accessory Strobe for Cameras with Battery Enclosed Film Pack", by Richard C. Kee, issued Feb. 14, 1978, in common assignment herewith, or U.S. Pat. No. 4,231,645, entitled "Camera with Telescoping Dual Actuators", by Carl W. Davis et al., issued Nov. 4, 1980, in common assignment herewith. However, powering both the film transport motor as well as the electronic flash presents a high power drain to the battery which could potentially result in a battery failure prior to the exposure of all the film units in the film cassette. Such a battery failure would become likely if the user should turn on the flash and leave it to operate in a continuous charging mode over an extended period of time.
Thus, it has been recognized that the operation of the film transport motor and the charging of the electronic flash must be sequentially timed so as not to occur simultaneously as fully described in U.S. Pat. No. 3,846,812, entitled "Automatic Electronic Flash Camera", by Conrad H. Biber, issued Nov. 5, 1974, in common assignment herewith and now incorporated by reference herein. In the aforementioned camera, once the exposed film unit has been transported and ejected from the camera, the electronic flash is sequenced to charge in readiness for the next succeeding photographic exposure operation. Thus, a photographer perceives the termination of the first photographic exposure cycle when the exposed film unit is ejected from the camera whereupon he must thereafter wait for the electronic flash to become fully charged before implementing the next succeeding photographic exposure cycle. Since the photographer readily perceives the ejection of the exposed film unit as the final act in the exposure cycle, the subsequent time required to charge the electronic flash before the next succeeding photographic exposure cycle can be initiated is readily apparent to him and may appear to be exceedingly long even if in fact it is only a matter of seconds, particularly if the photographer is anxious to implement the next succeeding photographic exposure cycle. However, as previously discussed, the charging of the electronic flash cannot be accomplished during the operation of the film transport motor because of an excessive drain upon the film cassette battery.
Therefore, it is a primary object of this invention to provide a photographic camera system wherein the apparent charging time for an electronic flash subsequent to the ejection and transfer of an exposed film unit from the camera is shortened by a predetermined charge interval sneaked in prior to the operation of the film transport motor.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the mechanism and system possessing the construction, the combination of elements and the arrangement of parts which are exemplified in the following detailed disclosure.